MASTIGOPHORA 



59 



2. They often have more than two flagella. This is very rare in the 

 Phytomastigina. 



Fig. 44, Volvox aureus. After Klein, a (x 180), A medium-sized colony 

 showing as round black dots the numerous "somatic cells" of which it is 

 made up; the protoplasmic connections between them, and the cell-walls, 

 can only be made visible by staining. The colony contains three types of re- 

 productive units : daughter colonies (d.c.) produced asexually by division of 

 a single zooid; ripe macrogametes or young zygotes (z); and young "an- 

 theridia" (an) whose contents are dividing up and will eventually form 

 microgametes. b, A colony of microgametes which has just escaped from the 

 antheridium. c, Mature antheridia as seen in surface view of a colony; in two 

 the microgametes are seen sideways, and in two endways. 



3. With a single exception,^ it has not yet been established that 

 syngamy occurs in any of them. 



4. Many of their parasitic members possess parabasal bodies. 



^ Helkesimastix, a coprozoicmember of the Protomonadina, performs hologamy. 



